This invention relates to a magnetic recording medium of coating type having a magnetic layer containing hexagonal plate magnetic powder. More particularly, it relates to such a magnetic recording medium in the form of a disk having improved runnability, overwriting ability, and output.
In recent years, it is strongly desired in the field of magnetic recording to increase recording density to provide for expanded recording capacity and compactness. Among coating type magnetic recording media having the inherent advantage of productivity, most widely used are those having a magnetic layer containing needle magnetic powder such as .gamma.-Fe.sub.2 O.sub.3 and cobalt-coated .gamma.-Fe.sub.2 O.sub.3. However, these magnetic recording media using such magnetic powder have a certain limit in recording density.
In order to achieve a higher recording density, a new system is proposed which utilizes the residual magnetization of a magnetic recording medium in a direction perpendicular to its major plane. The perpendicular magnetizable layer of such media contains hexagonal plate magnetic powder, for example, barium ferrite and strontium ferrite. These perpendicular magnetic recording media offer a higher recording density, but suffer from several problems when formed as magnetic disks which are operated with conventional ring-type magnetic heads. That is, the perpendicular magnetic recording disks are insufficient in runnability, overwriting characteristics and output, and suffer from dynamic durability during operation. There is a need for improvements in these respects.